Incidental pathologic extracardiac uptake of 99mTc-tetrofosmin in myocardial perfusion imaging.

Technetium-99m-tetrofosmin ((99m)Tc-TF) myocardial perfusion studies have incidentally detected various extracardiac abnormalities. The interpretation of these findings may be essential for early diagnosis and treatment of important diseases. We present a rare case of a mediastinal thymoma incidently detected during myocardial perfusion imaging. A 60 year-old woman, with precardiac symptoms of possible myocardial ischemia, underwent a (99m)Tc-TF stress-rest single photon emission tomography test. Intense uptake of the radiotracer in the left paracardiac area, was observed. The computerized tomography and the magnetic resonance imaging tests revealed a mass in the left lower anterior mediastinal area. Biopsy and subsequent histology showed that this mass was a thymoma.